(a) Field of the Invention
This invention relates to a process for stripping a layer of paint from the surface of a support. More particularly, the invention relates to a pre-treatment of the support before forming a layer of paint thereon.
(b) Description of Prior Art
On a technical aspect, it is known to strip a layer of paint from an object, so as to suitably revarnish the latter or to remove the paint therefrom, whether the latter is temporary, non desired or unavoidable.
In the present description, and for simplification, the technique of stripping a layer of paint from an object will be referred to by the .term "stripping".
With respect to the problem, which is the object of the present patent, we know, for example, that after many cycles of work, the frames of painting installations are unusable because of the thick layer of accumulated paint which, on the one hand results from an excessive utilization of paint and, on the other hand, implies a heat consumption waste during the polymerization reaction at the stage where said paint is baked in an oven. Moreover, there are other problems such as the substantial weight increases and the progressive thermic insulation of the frames, which render all the electrostatic methods of varnishing inefficient. It is therefore necessary to replace the frames or to strip the layers of varnishing product which have accumulated to give them their original aspect, such as by "stripping".
The technique which is known has proposed many methods of stripping.
According to Italian Patent Application No. 0915 A/86, the layers of paint covering a support can be stripped by breaking down these layers by cooling at low temperature with liquefied gases and, eventually, executing a corresponding final mechanical stripping.
This technique of immersion in liquefied gas is relatively efficient but can often have anti-economical aspects insofar as the use and consumption of large quantities of said gas and the necessity of an extended mechanical action with installation and management costs.